|SREL Reprint #0894|
Biochemical Genetics of Mosquitofish.
II. Demographic Differentiation of Populations in a Thermally Altered
L. Feder, Michael H. Smith, Ronald K. Chesser, Mary Jo W. Godt and Kenneth
Mosquitofish (N=7,580) from five sites along a
thermal gradient in a reservoir were analyzed using electrophoretic techniques.
Each sample was genetically different from the other four and none was in
Hardy-Weinberg equilibrium for all loci. The
populations also differed in their sex ratios and size structures.
Juveniles tended to be less heterozygous than adults and heterozygotes
tended to have longer body lengths than homozygotes within sex-age classes as
indicated by single locus tests. Overall
heterozygosity was highest in the population from the hottest water and lowest
in those populations from the coldest water.
Distributions of fish with different numbers of heterozygous loci were
similar among sex-age classes within locations but significantly different for
males and juveniles across locations. While
sochastic processes are important in determining some of the genetic variations
of the mosquitofish populations, selection is the probable explanation for the
body length-genotype correlations and for the differences in genotypic
proportions between males, females and juveniles.
SREL Reprint #0894
Feder, J.L., M.H. Smith, R.K. Chesser, M.J.W. Godt,
and K. Asbury. 1984. Biochemical genetics of mosquitofish. II.
Demographic differentiation of populations in a thermally altered
reservoir. Copeia 1984:108-119.